Resonator element, resonator, oscillator, and electronic device

ABSTRACT

A resonator element capable of improving impact resistance is provided. A quartz crystal resonator element is a resonator element formed by etching a Z plate which is cut at predetermined angles with respect to the crystal axes of a quartz crystal. The quartz crystal resonator element includes a base, a pair of resonating arms extending from the base in the Y-axis direction, and a positive X-axis notch and a negative X-axis notch formed by notching the base in the X-axis direction. The positive X-axis notch is formed by notching the base from the negative side of the X axis towards the positive side so that the width of the positive X-axis notch increases as it approaches the outer circumference.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Ser. No.13/030,449 filed Feb. 18, 2011 which claims priority to Japanese PatentApplication Nos. 2010-039785 filed Feb. 25, 2010 and 2010-268087 filedDec. 1, 2010 all of which are incorporated by reference in theirentireties.

BACKGROUND

1. Technical Field

The present invention relates to a resonator element, a resonator havingthe resonator element, an oscillator having the resonator element, andan electronic device having the resonator element.

2. Related Art

JP-A-2002-280870 discloses a resonator element which includes a base anda resonating arm portion (hereinafter, referred to as a resonating arm)protruding from the base, and in which a groove is formed in theresonating arm, and a cut-out portion (hereinafter, referred to as anotch) is formed in the base.

In the resonator element disclosed in JP-A-2002-280870, since a notch isformed in the base, a leakage of vibration from the resonating arm tothe base decreases. Thus, it is possible to suppress fluctuation of theCI (Crystal Impedance) value (Q value).

The outer shape of the resonator element is generally formed by etching.A resonator element made from a quartz crystal has etching anisotropy:that is, the etching rate differs depending on the direction withrespect to the quartz crystal axes of the quartz crystal.

Due to this etching anisotropy, the resonator element at the tip end ofthe notch in the base is over-etched (excessively etched). Thus, thenotch goes further into the central side of the base from an originalposition. As a result, the notch has a shape, such as a wedge with anacute tip end, such that stress is likely to be concentrated on it.

When an impact, such as by being dropped, is applied to the resonatorelement, stress is concentrated on the tip end of the notch, andbreaking may start from that portion.

SUMMARY

An advantage of some aspects of the invention is to solve at least apart of the problems described above and the invention can beimplemented as the following forms or application examples.

Application Example 1

According to this application example of the invention, there isprovided a resonator element whose outer shape is formed by etching a Zplate which is cut at predetermined angles with respect to the mutuallyorthogonal X, Y, and Z axes which are the crystal axes of a quartzcrystal, including: a base having a notch; and a resonating armextending from the base, wherein the notch includes a positive X-axisnotch formed by notching the base from the negative side of the X axisto the positive side, wherein a width in the Y-axis direction of thepositive X-axis notch reaches the maximum at a negative X axis-side endof the positive X-axis notch, and wherein the base has a shape such thatthe width of the positive X-axis notch gradually decreases from thenegative X axis-side end towards the positive side of the X axis.

According to this configuration, the resonator element includes thenotch which includes the positive X-axis notch formed by notching thebase from the negative side of the X axis towards the positive side.

Since the resonator element is provided with the notch in theabove-mentioned direction, it is possible to suppress vibration leakagemore effectively. Moreover, since the resonator element has a slopeportion in the base, the etching rate changes at the tip end of thenotch. Thus, it is possible to suppress over-etching.

As a result, since the concentration of stress in the tip end of thenotch is suppressed in the resonator element, the strength of the baseis improved. Thus, it is possible to improve impact resistance of thequartz crystal resonator element.

Application Example 2

According to this application example, in the resonator element of theabove application example, the base has a slope portion sloped so thatthe width of the positive X-axis notch decreases from the negative Xaxis-side end towards the positive side of the X axis.

According to this configuration, the base of the resonator element hasthe slope portion sloped so that the width of the positive X-axis notchdecreases from the negative X axis-side end towards the positive side ofthe X axis. Since the resonator element is provided with the slopeportion in the base, the etching rate changes at the tip end of thepositive X-axis notch. Thus, it is possible to suppress over-etching.

As a result, since the concentration of stress in the tip end of thenotch is suppressed in the resonator element, the strength of the baseis improved. Thus, it is possible to improve impact resistance.

Application Example 3

In the resonator element of the above application example, it ispreferable that the slope portion is connected to one side of the notchpositioned on the positive side of the Y axis, and the angle between theslope portion and the side is within the range of 3° to 35°.

According to this configuration, the resonator element is configured sothat the angle between the slope portion and the side of the notchpositioned on the positive side of the Y axis is within the range of 3°to 35°.

Since the resonator element is configured so that the angle between theslope portion and the side is within the above-mentioned range, it ispossible to suppress over-etching effectively. The present inventorsfound the above-mentioned range from the analysis results of an etchingsimulation upon verification of compatibility with actual products.

Application Example 4

In the resonator element of the above application example, it ispreferable that the slope portion is connected to the other side of thenotch positioned on the negative side of the Y axis, and an anglebetween the slope portion and the other side is within the range of 10°to 30°.

According to this configuration, the resonator element is configured sothat the angle between the slope portion and the other side of the notchpositioned on the negative side of the Y axis is within the range of 10°to 30°.

Since the resonator element is configured so that the angle between theslope portion and the other side is within the above-mentioned range, itis possible to suppress over-etching effectively. The present inventorsfound the above-mentioned range from the analysis results of an etchingsimulation after verification of compatibility with actual products.

Application Example 5

In the resonator element of the above application example, it ispreferable that the notch includes a negative X-axis notch formed bynotching the base from the positive side of the X axis towards thenegative side, and the positive X-axis notch and the negative X-axisnotch are formed at the same position in the Y-axis direction.

According to this configuration, the resonator element is configured sothat the notch is provided as a pair of notches including the positiveX-axis notch and the negative X-axis notch and is formed in a symmetricshape with respect to the central line of the base along the extensiondirection of the resonating arm. Thus, it is possible to obtain awell-balanced vibration.

Application Example 6

In the resonator element of the above application example, it ispreferable that a plurality of the resonating arms is provided, and theplurality of resonating arms and the base form a tuning fork.

According to this configuration, the resonator element includes aplurality of the resonating arms, and the plurality of resonating armsand the base form a tuning fork. Thus, it is possible to provide aresonator element having improved impact resistance.

Application Example 7

According to this application example of the invention, there isprovided a resonator including: the resonator element of the aboveapplication example; and a package that accommodates the resonatorelement.

According to this configuration, since the resonator includes theresonator element having improved impact resistance, it is possible toimprove impact resistance of the resonator.

Application Example 8

According to this application example of the invention, there isprovided an oscillator including: the resonator element of the aboveapplication example; a circuit element that has an oscillation circuitoscillating the resonator element; and a package that accommodates theresonator element and the circuit element.

According to this configuration, since the oscillator includes theresonator element having improved impact resistance, it is possible toimprove impact resistance of the oscillator.

Application Example 9

According to this application example of the invention, there isprovided an electronic device including: the resonator element of theabove application example; and a circuit element that has an oscillationcircuit oscillating the resonator element.

According to this configuration, since the electronic device includesthe resonator element having improved impact resistance, it is possibleto improve the impact resistance of the electronic device.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIGS. 1A and 1B are schematic views showing a simplified configurationof a resonator element according to a first embodiment, in which FIG. 1Ais a top view, and FIG. 1B is a cross-sectional view of FIG. 1A.

FIG. 2 is an enlarged view of a main part of FIG. 1A.

FIG. 3 is a table showing the relationship between an angle of a slopeportion in a notch and an etching shape of a tip end.

FIGS. 4A and 4B are schematic views showing a simplified configurationof a resonator element according to a second embodiment, in which FIG.4A is a top view, and FIG. 4B is a cross-sectional view of FIG. 4A.

FIG. 5 is an enlarged view of a main part of FIG. 4A.

FIG. 6 is a table showing the relationship between an angle of a slopeportion in a notch and an etching shape of a tip end.

FIGS. 7A and 7B are schematic views showing a simplified configurationof a resonator according to a third embodiment, in which FIG. 7A is atop view, and FIG. 7B is a cross-sectional view of FIG. 7A.

FIGS. 8A and 8B are schematic views showing a simplified configurationof an oscillator according to a fourth embodiment, in which FIG. 8A is atop view, and FIG. 8B is a cross-sectional view of FIG. 8A.

FIG. 9 is a perspective view showing a simplified configuration of aportable phone as an example of an electronic device according to theinvention.

FIG. 10 is a circuit block diagram of the portable phone as an exampleof an electronic device according to the invention.

FIG. 11 is a perspective view showing a simplified configuration of apersonal computer as an example of an electronic device according to theinvention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, exemplary embodiments of the present invention will bedescribed with reference to the drawings.

First Embodiment

FIGS. 1A and 1B are schematic views showing a simplified configurationof a resonator element according to a first embodiment, in which FIG. 1Ais a top view, and FIG. 1B is a cross-sectional view taken along theline IB-IB in FIG. 1A. FIG. 2 is an enlarged view of a “B” part in FIG.1A.

As shown in FIGS. 1A and 1B, a quartz crystal resonator element 1 as aresonator element is a resonator element whose outer shape is formed byphotolithographically etching (wet-etching) a Z plate which is cut, forexample, from quartz crystal ore, at predetermined angles with respectto the mutually orthogonal X, Y, and Z axes which are the crystal axesof a quartz crystal. In this embodiment, etching is performed using anetching solution containing hydrofluoric acid.

Here, the Z plate means a plate whose cutting surface (principal surface10 a) is approximately orthogonal to the Z axis. Thus, the Z plate alsoincludes a plate whose principal surface 10 a orthogonal to the Z axisis cut in a state where the surface is rotated within the range of 0° toseveral degrees in the counterclockwise or clockwise direction from theY axis to the Z axis as seen from the positive side of the X axis.

The quartz crystal resonator element 1 is cut from a single crystal ofthe quartz crystal so that the electrical axis is on the X axis, themechanical axis is on the Y axis, and the optical axis is on the Z axis.

In the quartz crystal resonator element 1, a Z plate extending along theX-Y plane which exists on the X and Y axes and which is tilted at anangle of 0° to 5° around the X axis as seen from the intersection (theorigin of coordinates) of the X and Y axes can be used.

The quartz crystal resonator element 1 allows the error of the cuttingangle from the crystal within a certain range (for example, about 0° to5°) with respect to each of the X, Y, and Z axes.

The quartz crystal resonator element 1 includes a base 10, a pair ofresonating arms 11 extending approximately in parallel from the base 10in the Y-axis direction, and a pair of supporting portions 14 protrudingfrom the base 10 in the X-axis direction, bent towards the resonatingarms 11, and extending in the Y-axis direction. In the base 10, a pairof notches which is notched in the X-axis direction is formed. That is,a positive X-axis notch 12 is notched from the negative side of the Xaxis towards the positive side, and a negative X-axis notch 13 isnotched from the positive side of the X axis towards the negative side.

The quartz crystal resonator element 1 includes the base 10 and the pairof resonating arms 11 which form a tuning fork, whereby a tuningfork-type resonator element is obtained. The quartz crystal resonatorelement 1 is fixed to an external member such as a package through amount electrode (not shown) formed at a predetermined position of eachof the supporting portions 14.

The resonating arm 11 includes an arm portion 15 positioned close to thebase 10, a weight portion 16 positioned further close to the tip endthan the arm portion 15 and having a larger width than the arm portion15, and a groove 17 formed along the extension direction (Y-axisdirection) of the resonating arm 11 and cut along the arrangementdirection (X-axis direction) of the pair of resonating arms 11 so thatthe resonating arm 11 has an H-shape in cross-sectional view.

In the quartz crystal resonator element 1, when an external drivingsignal is applied through the mount electrode to an excitation electrode(not shown) formed on the resonating arms 11, the pair of resonatingarms 11 alternately vibrate (resonate) in the flexural mode at apredetermined frequency (for example, 32 kHz) in the directionsindicated by the arrows C and D.

Next, the pair of notches (the positive X-axis notch 12 notched from thenegative side of the X axis towards the positive side and the negativeX-axis notch 13 notched from the positive side of the X axis towards thenegative side) will be described in detail.

The positive X-axis notch 12 is formed by notching the base 10 from thenegative side of the X axis towards the positive side.

As shown in FIG. 2, the base 10 has a slope portion 12 c which isdisposed between the outer circumference 10 b of the base 10 and a side12 a as one side positioned close to the positive side of the Y axis,between the two sides 12 a and 12 b in the notching direction of thepositive X-axis notch 12. The slope portion 12 c is formed so that thewidth of the positive X-axis notch 12 increases as it approaches theouter circumference 10 b. In other words, the positive X-axis notch 12has a shape such that the width in the Y-axis direction of the positiveX-axis notch 12 reaches the maximum at the position of the outercircumference 10 b of the base 10 which is the negative X axis-side endof the positive X-axis notch 12, and the width gradually decreases fromthe outer circumference 10 b which is the negative X axis-side endtowards the positive side of the X axis.

As described above, the slope portion 12 c is connected to the side 12 aof the positive X-axis notch 12 positioned on the positive side of the Yaxis, and the angle θ between the slope portion 12 c and the side 12 ais within the range of 3° to 35°.

On the other hand, as shown in FIG. 1A, the negative X-axis notch 13 isprovided to be paired with the positive X-axis notch 12 and is formed ina symmetric shape to the positive X-axis notch 12 with respect to thecentral line 10 c of the base 10 along the extension direction (Y-axisdirection) of the resonating arm 11.

Next, the relationship between the angle θ of the slope portion 12 c ofthe positive X-axis notch 12 and the etching shape of the tip end of thepositive X-axis notch 12 will be described based on the analysis resultsof a simulation by the present inventors.

FIG. 3 is a table showing the relationship between the angle of a slopeportion in a notch and an etching shape of a tip end.

The etching shape obtained through the simulation is evaluated intothree grades: X (Poor), O (Good), and © (Excellent) in the descendingorder of the possibility of stress concentration. If the etching shapeis evaluated as O or ©, it can be determined that stress concentrationrarely occurred and the resonator elements can be used formass-production.

As shown in FIG. 3, the etching shape is evaluated as O or better whenthe angle θ of the slope portion 12 c is within the range of 3° to 35°,and particularly, is evaluated as © for the range of 10° to 30°. Incontrast, the etching shape is evaluated as X when the angle θ of theslope portion 12 c is 0°, 37°, and 40°.

According to the analysis results, the angle θ of the slope portion 12 cis preferably in the range of 3° to 35°, and more preferably, in therange of 10° to 30°. Moreover, it is particularly preferable that theangle θ is about 30° from the perspective of the forming precision ofthe slope portion 12 c which is influenced by etching anisotropy.

The etching shape obtained through the simulation will be described indetail. The two-dot chain line in FIG. 2 shows the shape of the tip endwhen there is no slope portion 12 c (which is the shape obtained withthe related art, and is the case where the angle θ in FIG. 3 is 0°).

In this case, the tip end of the positive X-axis notch 12 is soover-etched as to go further into the center side of the base 10 thanthe intended original circular-arc shape indicated by the solid line. Asa result, the tip end has a shape, such as a wedge with an acute tipend, such that stress is likely to be concentrated on it.

In contrast, when the angle θ of the slope portion 12 c is within therange of 3° to 35°, the etching rate changes at the tip end of thepositive X-axis notch 12. Thus, the over-etching is suppressed. As aresult, the tip end of the positive X-axis notch 12 has a shape close tothe intended circular-arc shape indicated by the solid line.

As described above, the quartz crystal resonator element 1 according tothe first embodiment has the positive X-axis notch 12 and the negativeX-axis notch 13 which are formed by notching the base 10 in the X-axisdirection. Moreover, the quartz crystal resonator element 1 has theslope portion 12 c which is disposed between the outer circumference 10b of the base 10 and the side 12 a of the positive X-axis notch 12positioned close to the positive side of the Y axis among the two sides12 a and 12 b in the notching direction of from the negative side of theX axis to the positive side, and which is formed so that the width ofthe positive X-axis notch 12 increases as it approaches the outercircumference 10 b.

According to this configuration, since the quartz crystal resonatorelement 1 is provided with the positive X-axis notch 12 and the negativeX-axis notch 13 in the above-mentioned direction, it is possible tosuppress vibration leakage more effectively.

Moreover, since the quartz crystal resonator element 1 has the slopeportion 12 c in the positive X-axis notch 12, the etching rate changesat the tip end of the positive X-axis notch 12. Thus, it is possible tosuppress over-etching.

As a result, since the concentration of stress in the tip end of thepositive X-axis notch 12 is suppressed in the quartz crystal resonatorelement 1, the strength of the base 10 is improved. Thus, it is possibleto improve the impact resistance of the quartz crystal resonator element1.

Moreover, in the quartz crystal resonator element 1, when the angle θbetween the slope portion 12 c and the side 12 a is within the range of3° to 35°, it is possible to suppress over-etching effectively. When theangle θ between the slope portion 12 c and the side 12 a is within therange of 10° to 30°, it is possible to suppress over-etching moreeffectively.

Although the slope portion 12 c is described as having a linear shape,the invention is not limited to this, and for example, the slope portion12 c may have a circular-arc shape, a stepped shape, and the like. Inother words, the positive X-axis notch 12 may have a shape such that thewidth in the Y-axis direction of the positive X-axis notch 12 reachesthe maximum at the negative X axis-side end (the outer circumference 10b of the base 10) of the positive X-axis notch 12 and graduallydecreases from the negative X axis-side end (the outer circumference 10b of the base 10) towards the positive side of the X axis.

Moreover, the quartz crystal resonator element 1 is configured so thatthe positive X-axis notch 12 and the negative X-axis notch 13 areprovided in a paired manner, and the positive X-axis notch 12 and thenegative X-axis notch 13 are formed in a symmetric shape with respect tothe central line 10 c of the base 10 along the extension direction(Y-axis direction) of the resonating arm 11. Thus, it is possible toobtain a well-balanced flexural vibration.

Moreover, the quartz crystal resonator element 1 includes a pair (two)of resonating arms 11, and the two resonating arms 11 and the base 10form a tuning fork. Thus, it is possible to provide a tuning fork-typeresonator element having improved impact resistance.

Moreover, since the quartz crystal resonator element 1 is configured sothat the tip end of the negative X-axis notch 13 is rarely over-etcheddue to etching anisotropy of a quartz crystal, the slope portion may notbe provided in the negative X-axis notch 13.

Second Embodiment

FIGS. 4A and 4B are schematic views showing a simplified configurationof a resonator element according to a second embodiment used in anelectronic device according to the invention, in which FIG. 4A is a topview, and FIG. 4B is a cross-sectional view taken along the line IVB-IVBin FIG. 4A. FIG. 5 is an enlarged view of a “F” part in FIG. 4A.

The same portions as the first embodiment will be denoted by the samereference numerals, and description thereof is omitted. In the followingdescription, only the portions different from those of the firstembodiment will be described.

As shown in FIGS. 4A and 4B, a quartz crystal resonator element 2 as aresonator element is different from that of the first embodiment, inthat the positive X-axis notch 12 and the negative X-axis notch 13 areshaped differently.

As shown in FIG. 5, the base 10 of the quartz crystal resonator element2 has a slope portion 12 d which is disposed between an outercircumference 10 b of the base 10 and a side 12 b as the other sidepositioned close to the negative side of the Y axis, among the two sides12 a and 12 b in the notching direction of the positive X-axis notch 12.The slope portion 12 d is formed so that the width of the positiveX-axis notch 12 increases as it approaches the outer circumference 10 b.In other words, the positive X-axis notch 12 has a shape such that thewidth in the Y-axis direction of the positive X-axis notch reaches themaximum at the position of the outer circumference 10 b of the base 10which is the negative X axis-side end of the positive X-axis notch 12,and the width gradually decreases from the outer circumference 10 bwhich is the negative X axis-side end towards the positive side of the Xaxis.

As described above, the slope portion 12 d is connected to the side 12 bof the positive X-axis notch 12 positioned on the negative side of the Yaxis, and the angle θ1 between the slope portion 12 d and the side 12 bis within the range of 10° to 30°.

On the other hand, as shown in FIG. 4A, the negative X-axis notch 13 isprovided to be paired with the positive X-axis notch 12 and is formed ina symmetric shape to the positive X-axis notch 12 with respect to thecentral line 10 c of the base 10 along the extension direction (Y-axisdirection) of the resonating arm 11.

Next, the relationship between the angle θ1 of the slope portion 12 d ofthe positive X-axis notch 12 and the etching shape of the tip end of thepositive X-axis notch 12 will be described based on the analysis resultsof a simulation by the present inventors.

FIG. 6 is a table showing the relationship between an angle of a slopeportion in a notch and an etching shape of a tip end.

The etching shape obtained through the simulation is evaluated into twogrades: X (Poor) and O (Good) in the descending order of the possibilityof stress concentration. If the etching shape is evaluated as O, it canbe determined that stress concentration rarely occurred and theresonator elements can be used for mass-production.

As shown in FIG. 6, the etching shape is evaluated as O when the angleθ1 of the slope portion 12 d is within the range of 10° to 30°. Incontrast, the etching shape is evaluated as X when the angle θ1 of theslope portion 12 d is 0°.

According to the analysis results, the angle θ1 of the slope portion 12d is preferably in the range of 10° to 30°.

The etching shape obtained through the simulation will be described indetail. The two-dot chain line in FIG. 5 shows the shape of the tip endwhen there is no slope portion 12 d (which is the shape obtained withthe related art, and is the case where the angle θ in FIG. 6 is 0°).

In this case, like the first embodiment, the tip end of the positiveX-axis notch 12 is over-etched too much to go further into the centerside of the base 10 than an intended original circular-arc shapeindicated by the solid line. As a result, the tip end has a shape, suchas a wedge with an acute tip end, such that stress is likely to beconcentrated on it.

In contrast, when the angle θ1 of the slope portion 12 d is within therange of 10° to 30°, the etching rate changes at the tip end of thepositive X-axis notch 12. Thus, the over-etching is suppressed. As aresult, the tip end of the positive X-axis notch 12 has a shape close tothe intended circular-arc shape indicated by the solid line.

As described above, the base 10 of the quartz crystal resonator element2 according to the second embodiment has the slope portion 12 d which isdisposed between the outer circumference 10 b of the base 10 and theside 12 b of the positive X-axis notch 12 positioned close to thenegative side of the Y axis among the two sides 12 a and 12 b in thenotching direction, and which is formed so that the width of thepositive X-axis notch 12 increases as it approaches the outercircumference 10 b.

Moreover, the quartz crystal resonator element 2 is configured so thatthe angle θ1 between the slope portion 12 d and the side 12 b is withinthe range of 10° to 30°.

According to this configuration, in the quartz crystal resonator element2, the etching rate changes at the tip end of the positive X-axis notch12. Thus, it is possible to suppress over-etching.

As a result, since the concentration of stress in the tip end of thepositive X-axis notch 12 is suppressed in the quartz crystal resonatorelement 2, the strength of the base 10 is improved. Thus, it is possibleto improve the impact resistance of the quartz crystal resonator element2.

Moreover, since the quartz crystal resonator element 2 is configured sothat the tip end of the negative X-axis notch 13 is rarely over-etcheddue to etching anisotropy of a quartz crystal, the slope portion may notbe provided in the negative X-axis notch 13.

Although in the embodiments described above, the number of resonatingarms 11 has been set to be two, the invention is not limited to this,the number of resonating arms 11 may be one or three or more.

Moreover, the supporting portion 14, the weight portion 16, and thegroove 17 may not be provided. Moreover, the direction of the flexuralvibration of the resonating arm 11 may be the thickness direction(Z-axis direction) of the resonating arm 11. Furthermore, the slopeportion 12 c and the slope portion 12 d may be provided together.

Third Embodiment

Next, a resonator having the quartz crystal resonator element describedabove will be described as a third embodiment.

FIGS. 7A and 7B are schematic views showing a simplified configurationof a resonator according to a third embodiment, in which FIG. 7A is atop view, and FIG. 7B is a cross-sectional view taken along the lineVIIB-VIIB in FIG. 7A.

As shown in FIGS. 7A and 7B, a quartz crystal resonator 5 as a resonatorincludes the quartz crystal resonator element 1 of the first embodimentand a package 80 that accommodates the quartz crystal resonator element1.

The package 80 includes a package base 81, a seam ring 82, a cover 85,and the like.

The package base 81 has a recess so that the quartz crystal resonatorelement 1 can be accommodated therein, and connection pads 88 connectedto the mount electrodes (not shown) of the quartz crystal resonatorelement 1 are provided in the recess.

The connection pads 88 are connected to wirings inside the package base81 so as to be electrically connected to an external connection terminal83 provided at the periphery of the package base 81.

The seam ring 82 is provided around the recess of the package base 81. Apenetration hole 86 is provided on the bottom of the package base 81.

The quartz crystal resonator element 1 is attached and fixed to theconnection pads 88 of the package base 81 by a conductive adhesive 84.In the package 80, the cover 85 covering the recess of the package base81 is seam-welded to the seam ring 82.

A sealing material 87 made from a metal material or the like is filledin the penetration hole 86 of the package base 81. The sealing material87 is melted in a depressurized atmosphere and solidified to airtightlyseal the penetration hole 86 so that the inside of the package base 81is maintained in the depressurized state.

The quartz crystal resonator 5 oscillates at a predetermined frequency(for example, 32 kHz) when the quartz crystal resonator element 1 isexcited by an external driving signal supplied through the externalconnection terminal 83.

As described above, since the quartz crystal resonator 5 includes thequartz crystal resonator element 1 having improved impact resistance, itis possible to improve the impact resistance of the quartz crystalresonator 5.

The same advantage can be obtained when the quartz crystal resonator 5includes the quartz crystal resonator element 2 in place of the quartzcrystal resonator element 1.

Fourth Embodiment

Next, an oscillator having the quartz crystal resonator elementdescribed above will be described as a fourth embodiment.

FIGS. 8A and 8B are schematic views showing a simplified configurationof an oscillator according to a fourth embodiment, in which FIG. 8A is atop view, and FIG. 8B is a cross-sectional view taken along the lineVIIIB-VIIIB in FIG. 8A.

A crystal oscillator 6 as an oscillator has a configuration in which thequartz crystal resonator 5 described above further includes a circuitelement. The same portions as the quartz crystal resonator 5 will bedenoted by the same reference numerals, and description thereof isomitted.

As shown in FIGS. 8A and 8B, the crystal oscillator 6 includes thequartz crystal resonator element 1 of the first embodiment, an IC chip91 as a circuit element having an oscillation circuit that oscillatesthe quartz crystal resonator element 1, and the package 80 thataccommodates the quartz crystal resonator element 1 and the IC chip 91.

The IC chip 91 is attached to the bottom of the package base 81 and isconnected to other wirings by metal wires 92 such as gold wires.

The crystal oscillator 6 oscillates at a predetermined frequency (forexample, 32 kHz) when the quartz crystal resonator element 1 is excitedby a driving signal supplied from the oscillation circuit of the IC chip91.

As described above, since the crystal oscillator 6 includes the quartzcrystal resonator element 1 having improved impact resistance, it ispossible to improve the impact resistance of the crystal oscillator 6.

The same advantage can be obtained when the crystal oscillator 6includes the quartz crystal resonator element 2 in place of the quartzcrystal resonator element 1.

Electronic Device

The quartz crystal resonator elements of the respective embodimentsdescribed above can be applied to various electronic devices, and suchelectronic devices have high reliability. In this electronic device, theresonator and oscillator described in the embodiments may be used.

FIGS. 9 and 10 show a portable phone as an example of an electronicdevice according to the invention. FIG. 9 is a perspective view showinga simplified external appearance of the portable phone, and FIG. 10 is acircuit block diagram illustrating the circuit portion of the portablephone.

A portable phone 300 may use the quartz crystal resonator element 1 or 2described above. In this example, an example where the quartz crystalresonator element 1 is used will be described. Moreover, furtherdescription of the configuration and action of the quartz crystalresonator element 1 will be omitted by using the same reference numeralsas used in the above described embodiment.

As shown in FIG. 9, the portable phone 300 includes an LCD (LiquidCrystal Display) 301 which is a display section, a key 302 which is aninput section for inputting numbers or the like, a microphone 303, aspeaker 311, a circuit portion (not shown) which includes theoscillation circuit that oscillates the quartz crystal resonator element1, and the like.

As shown in FIG. 10, when a user inputs his/her voice into themicrophone 303 to perform communication using the portable phone 300,the voice signals are transmitted from an antenna 308 through apulse-width modulation/encoding block 304, a modulator/demodulator block305, a transmitter 306, and an antenna switch 307.

On the other hand, signals transmitted from a counterpart phone arereceived by the antenna 308 and input to the modulator/demodulator block305 through the antenna switch 307, a receiver filter 309, and areceiver 310. Moreover, the modulated or demodulated signals are outputfrom the speaker 311 as a sound through the pulse-widthmodulation/encoding block 304.

A controller 312 is provided so as to control the antenna switch 307,the modulator/demodulator block 305, and the like.

In addition to the above-mentioned components, the controller 312controls the LCD 301 which is a display section and the key 302 which isan input section for inputting numbers or the like, and further controlsa RAM 313, a ROM 314, and the like. Thus, higher precision is demanded.Moreover, there is also demand for miniaturization of the portable phone300.

To meet such a demand, the above-described quartz crystal resonatorelement 1 is used.

The portable phone 300 also includes a temperature-compensated crystaloscillator 315, a receiver synthesizer 316, a transmitter synthesizer317, and the like as its constituent blocks, and description thereof isomitted.

Since the quartz crystal resonator element 1 used in the portable phone300 is provided with the notch in the base 10, it is possible tosuppress vibration leakage more effectively. Moreover, since the quartzcrystal resonator element 1 has the slope portion 12 c in the notch, theetching rate changes at the tip end of the notch. Thus, it is possibleto suppress over-etching.

As a result, since the concentration of stress in the tip end of thenotch is suppressed in the quartz crystal resonator element 1, thestrength of the base 10 is improved. Thus, it is possible to improve theimpact resistance of the quartz crystal resonator element 1.

Therefore, the electronic device (the portable phone 300) using thequartz crystal resonator element 1 has stable characteristics, and theimpact resistance thereof can be improved.

FIG. 11 shows a personal computer (mobile personal computer) 400 asanother example of the electronic device having the quartz crystalresonator element 1 according to the invention. The personal computer400 includes a display section 401, an input key section 402, and thelike, and the quartz crystal resonator element 1 described above is usedas a reference clock for controlling the electrical operation thereof.

In addition to the above-mentioned examples, examples of the electronicdevice having the quartz crystal resonator element 1 according to theinvention include a digital-still camera, an ink jet ejection apparatus(for example, an ink jet printer), a laptop personal computer, atelevision, a video camera, a video tape recorder, a car navigationapparatus, a pager, an electronic pocket book (including one withcommunication capability), an electronic dictionary, a calculator, anelectronic game machine, a word processor, a work station, a televisionphone, a surveillance TV monitor, electronic binoculars, a POS terminal,a medical device (for example, an electronic thermometer, asphygmomanometer, a glucose meter, an electrocardiogram measuringsystem, an ultrasonic diagnosis device, and an electronic endoscope), afish finder, various measurement instruments, various indicators (forexample, indicators used in vehicles, airplanes, and ships), a flightsimulator, and the like.

While the electronic device according to the invention has beendescribed based on the embodiments, the invention is not limited to theembodiments, the configuration of the respective portions, units, andsections can be replaced with any configuration having the samefunction. Moreover, other arbitrary constituent elements may be added tothe invention. Furthermore, arbitrary two or more configurations(features) among the respective embodiments may be combined with eachother to implement the invention.

For example, although in the embodiments described above, a case wherethe quartz crystal resonator element has two resonating arms as thevibrating portions was described, the number of resonating arms may bethree or more.

Moreover, the quartz crystal resonator element described in theembodiment may be applied to a gyro sensor or the like, in addition to apiezoelectric oscillator such as a voltage-controlled crystal oscillator(VCXO), a temperature-compensated crystal oscillator (TCXO), or anoven-controlled crystal oscillator (OCXO).

1. A resonator element whose outer shape is formed by etching a Z platewhich is cut at predetermined angles with respect to the mutuallyorthogonal X, Y, and Z axes which are the crystal axes of a quartzcrystal, comprising: a base having a notch; and a resonating armextending from the base, wherein the notch includes a positive X-axisnotch formed by notching the base from the negative side of the X axisto the positive side of the X axis, wherein a width in the Y-axisdirection of the positive X-axis notch reaches the maximum at a negativeX axis-side end of the positive X-axis notch, and wherein the base has ashape such that the width of the positive X-axis notch graduallydecreases from the negative X axis-side end towards the positive side ofthe X axis.
 2. The resonator element according to claim 1, wherein thebase has a slope portion sloped so that the width of the positive X-axisnotch decreases from the negative X axis-side end towards the positiveside of the X axis.
 3. The resonator element according to claim 2,wherein the slope portion is connected to one side of the notchpositioned on the positive side of the Y axis, and an angle between theslope portion and the side is within the range of 3° to 35°.
 4. Theresonator element according to claim 2, wherein the slope portion isconnected to the other side of the notch positioned on the negative sideof the Y axis, and an angle between the slope portion and the other sideis within the range of 10° to 30°.
 5. The resonator element according toclaim 1, wherein the notch includes a negative X-axis notch formed bynotching the base from the positive side of the X axis towards thenegative side, and wherein the positive X-axis notch and the negativeX-axis notch are formed at the same position in the Y-axis direction. 6.The resonator element according to claim 1, wherein a plurality of theresonating arms is provided, and the plurality of resonating arms andthe base form a tuning fork.
 7. A resonator comprising: the resonatorelement according to claim 1; and a package that accommodates theresonator element.
 8. An oscillator comprising: the resonator elementaccording to claim 1; and a circuit element that has an oscillationcircuit oscillating the resonator element; and a package thataccommodates the resonator element and the circuit element.
 9. Anelectronic device comprising: the resonator element according to claim1; and a circuit element that has an oscillation circuit oscillating theresonator element.